BOGOTA, Colombia (CNN) -- Violent clashes between Indian protesters and riot police continued Wednesday in southwest Colombia, increasing the casualty toll to at least two dead and about 100 injured, according to Indian spokesmen.

Indians and riot police clash in Candelaria, in southern Colombia, on Tuesday.

The protests started Tuesday, when an estimated 7,000 Indians from various ethnic communities used rocks and tree trunks to block the Pan-American Highway -- the country's main north-south thoroughfare -- in at least four locations between Colombia's second largest city, Cali, and the city of Popayan, 85 miles (135 kilometers) to the south.

Fresh clashes broke out Wednesday when police moved in with armored personnel carriers and water cannons to clear the highway.

The Indians are protesting the Colombian government's free market economic policies; regional landowners they say have stolen their territory; and government plans for a free-trade deal with the United States. Watch Indian protesters prepare for battle »

The Indians, who are traditionally among the very poorest in Colombian society, along with blacks, say they are worse off than ever before.

Indian congressman Climaco Alvarez accused police of firing on protesters with live rounds Wednesday. Police deny using lethal force.

An Indian spokesman said one Indian was killed in Wednesday's clashes and 39 were injured. That adds to Tuesday's toll, given to CNN by another Indian spokesman, of one dead and around 60 injured.

Two hours after the clashes, the Indians said they had managed to move back onto the highway and set up fresh blockades.

Tuesday's clashes took place at several locations along the Pan-American Highway.

One spokesman for the National Indigenous Council told CNN that injuries to Indians, mostly of the Nasa tribe, had occurred in clashes with riot police near the southwest town of La Maria Piendamo and farther north near a community known as La Candelaria. He said 18 of the injured at La Maria Piendamo had gunshot wounds.

Col. Jorge Enrique Cartagena, commander of the police's elite riot squad, said his men had not used live rounds, only tear gas and water cannons.

He said seven of his men had been hurt, two seriously, by demonstrators who tossed rocks and fired stones from slingshots, and by exploding gunpowder.

He also said leftist guerrilla fighters of the Revolutionary Armed Forces of Colombia (FARC) had infiltrated the demonstration and were motivating the protest. Indian organizations deny the accusation, which law enforcement officials frequently level at social protests across the country.

The Pan-American Highway is a network of routes stretching from Alaska to South America's southern tip in Patagonia. The idea for it was conceived in 1923 to unite the Americas.

The road network is only broken at the jungle-covered border of Panama and Colombia -- a stretch of about 54 miles (87 kilometers) called the Darien Gap. Otherwise, the road network runs about 29,000 miles (48,000 kilometers).